Screw cap for a vessel

ABSTRACT

A cap for closing a threaded port in a vessel such as a pressure sprayer tank. A cup-shaped central portion of the cap faces into the vessel when the cap is installed onto the threaded port. The cup-shaped portion is provided with indicia indicative of volumes of material. In measuring use, the cap is inverted, allowing the cup-shaped portion be used as a measuring cup to which material may be added. When the desired amount has been added, the cap is re-inverted to dump the material into the vessel. Preferably, the cup-shaped portion has a skewed rim such that a portion of the rim forms a pouring lip. A pressure relief system permits relief of pressure when the vessel is opened at conclusion of use. Preferably, threads on the cap and the vessel are configured such that the cap seals against the vessel in one-quarter revolution of the cap.

[0001] The present application claims priority from U.S. Provisional Patent Application Ser. No. 60/474,069, and from U.S. Provisional Patent Application Ser. No. 60/474,100, both filed May 29, 2003.

TECHNICAL FIELD

[0002] The present invention relates to vessels having threaded ports; more particularly, to threaded caps for closing threaded ports in vessels; and most particularly, to an improved screw cap for closing a port in a vessel, especially a pressure vessel, and more especially, a loading port in a pump sprayer body.

BACKGROUND OF THE INVENTION

[0003] Vessels having entrance ports are well known. Typically, an entrance port requires a closure, which may be a screw cap having a threaded portion, either male or female, that engages a mating threaded portion, also either male or female, on the vessel. Such threads typically include several turns to distribute a pressure load in a vessel, which can require numerous rotations of a screw cap to seal. This can be an annoyance in vessels wherein the use requires frequent opening and closing of the loading port. Further, when there is residual pressure in the vessel at the time of re-opening, such pressure typically is relieved around the threads and may cause material within the vessel to be sprayed inadvertently in the vicinity of the cap, thereby endangering a user. When the threaded relationship is such that the vessel threads are female and the cap threads are male, such as in a typical prior art portable pump sprayer, the sprayed material can be ejected upwards from the vessel directly toward a user's face and eyes.

[0004] A typical prior art portable pump sprayer is vulnerable to all of the above-cited problems. In addition, use of a pump sprayer typically requires measuring and mixing of ingredients, for example, insecticides and/or fertilizers with water, and addition of the ingredients through a main loading port in the sprayer body, or tank. In the prior art, such measuring requires a separate measuring device, such as a measuring spoon or a measuring cup, which becomes contaminated by the act of measuring and must be cleaned subsequently. Furthermore, the contaminated measuring device cannot readily be set down before being cleaned without further contaminating the surface upon which it is set.

[0005] What is needed in the art of vessel closures is a threaded cap for sealing a vessel loading port that can relieve internal pressure from the vessel safely; preferably that can be secured to the vessel in less than one full turn; and that can function as a measuring device for liquids and/or granulated solids to be added to the vessel through the loading port.

SUMMARY OF THE INVENTION

[0006] Briefly described, a cap for closing a threaded port in a vessel includes a cup-shaped central portion facing into the vessel when the cap is installed onto the threaded port. The cup-shaped portion is provided with indicia, preferably in the form of numbered posts extending from the bottom of the cup to various heights, which are indicative of volumes of material placed in the cup-shaped portion. In use, the cap is inverted so that the cup-shaped portion is turned upwards and held level, allowing the cup-shaped portion be used as a measuring cup to which material may be added. When the desired amount has been added, as indicated by the appropriate depth-indicia, the cap is re-inverted to dump the material into the vessel. After the cap is screwed onto the loading port, the surfaces of the cup-shaped portion become part of the interior surface of the closed vessel. Thus, a separate measuring cup is not required for measuring ingredients to be added, as in the prior art. Preferably, the cup-shaped portion has an asymmetric rim such that a portion of the rim forms a pouring lip.

[0007] Preferably, the cap has a hub and a peripheral extension configured with female threads on the inner surface thereof and an axial surface inboard of the threads, preferably including an elastomeric seal such an O-ring, for sealing against an axial face on a male-threaded lip of the vessel. The cup-shaped portion is disposed within the cup axial sealing surface such that all exposure to the materials in the cup-shaped portion and the vessel is contained within the radius of the sealing surface.

[0008] Preferably, the cap includes pressure relief means formed within the cup-shaped portion such that material within the vessel is not expelled through the threads when the vessel is opened at conclusion of use.

[0009] Preferably, the mating threads on the cap and the vessel are configured such that the axial surface of the cap seals against the axial surface of the vessel in less than one revolution of the cap.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

[0011]FIG. 1 is an isometric view of a pressure vessel port and a cap in accordance with the invention;

[0012]FIG. 2 is an isometric view from below of the cap shown in FIG. 1, showing a cup-shaped central portion for use as a measuring cup;

[0013]FIG. 3 is an elevational cross-sectional view of the cap shown in FIGS. 1 and 2;

[0014]FIG. 4 is an isometric view from above of a cap for a pressure relief system in accordance with the invention;

[0015]FIG. 5 is an isometric view from below of the relief system cap shown in FIG. 4;

[0016]FIG. 6 is an elevational view of a case for a pressure relief system in accordance with the invention;

[0017]FIG. 7 is a cross-sectional view of the case shown in FIG. 6, taken along line 7-7 in FIG. 6;

[0018]FIG. 8 is an exploded isometric view of a pressure relief system in accordance with the invention; and

[0019]FIG. 9 is an isometric view of an alternative thread configuration for a vessel in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Referring to FIG. 1, a vessel 10, for example, a pressure tank for a hand-pumpable sprayer, includes a neck portion 12 defining a port 14 in vessel 10. Neck portion 12 is provided with threads 16 for securing a vessel cap 18 to vessel 10 to close port 14. Threads 16 may be either female or male but preferably are male, as shown in FIG. 1. Neck portion 12 terminates in a sealing edge 20 for engaging an O-ring 22 in compression between neck portion 12 and cap 18 as described in detail below.

[0021] Referring now to FIGS. 1, 2, and 3, cap 18 is generally convex upwards, having a peripheral extension 24 extending generally axially and connected to a hub portion 26. Preferably, the outer surface 28 of extension 24 is provided with a plurality of raised ribs 30 to assist in a user's gripping the cap to tighten or loosen the cap in use, and also preferably is provided with a designated area 32, preferably slightly recessed below surface 28, for receiving and displaying a label (not shown) identifying the contents of vessel 10 during any specific use thereof. Extension 24 is provided on an inner surface thereof with female threads 34 for engaging male threads 16 on neck portion 12. Extension 24 is reinforced at its attachment to hub 26 by a plurality of gussets 36. Extension 24 terminates outboard of gussets 36 in an annular axial surface 38 for receiving O-ring 22, as shown in FIG. 3, to seal cap 18 against neck portion 12 as described above.

[0022] On its outer axial surface, hub portion 26 preferably includes first and second hemispherical depressions 40 separated by a transverse flange 42 for providing gripping surfaces to augment ribs 30.

[0023] On its inner surface, a generally cylindrical wall 44 extends axially from hub portion 26 inboard of gussets 36, defining with hub portion 26 a cup-shaped portion 46 for use in measuring ingredients to be added to vessel 10, cap 18 being inverted from its use position such that portion 46 is concave upwards. Portion 46 preferably is provided with indicia for determining visually the amount of any ingredient in portion 46 during measurement thereof. For example, the inner surface 47 of wall 44 may be scribed or otherwise marked to show the amount of ingredients added, by depth thereof. In a currently-preferred embodiment, portion 46 is provided with a septum 48 extending diameterically across portion 46 and having a plurality of steps 50, each step being provided with an indicium 52 indicative of the volume of portion 46 between each step and hub portion 26. For example, one set of steps 50 a may be marked with indicia indicative of liquid ounces, while the other set of steps 50 b may be marked with indicia indicative of milliliters. Additional septa, steps, and indicia are fully comprehended by the present invention. Thus, cup-shaped portion 46 may be readily used to measure ingredients to be added to vessel 10 through port 14. Preferably, the rim 53 of wall 44 is assymetric (FIG. 3) to create a natural pouring lip 55 to facilitate the dumping of ingredients, and especially liquids, from the measuring cup into the vessel.

[0024] An important advantage of a measuring cup in accordance with the invention is that wall 44 extends into neck 12 when the cap is secured to the vessel; thus, any residual ingredients in cup-shaped portion 46 fall into and are added to the ingredients already in the vessel, and the surfaces of wall 44 are flushed by mixture in the vessel.

[0025] Hub portion 26 may be closed at its center; however, in a currently-preferred embodiment (referring now to FIGS. 2 through 8), a pressure relief system 60 is disposed through an axial aperture 61 (FIG. 2) in hub 26. System 60 includes a normally-closed valve and may be operated manually to vent pressure from vessel 10 as desired, and may also be sized in known fashion as a blow-off valve to vent vessel 10 if internal pressure exceeds a predetermined limit.

[0026] Relief system 60 comprises a cap 62 having a central aperture 64 and a plurality of radial lands 66 surrounding aperture 64 and extending axially from the underside of cap 62. A plunger 67 is surrounded by a return spring 68 which engages a flange 70 on plunger 67. Plunger 67 includes a head 72 which is forcibly extended through aperture 64 during assembly of system 60 to couple plunger 67 to cap 62; spring 68 is captured thereby in compression. A case 74 includes a generally cylindrical bore 76 having a seat 78 for receiving an inner O-ring 80. Seat 78 surrounds an axial outlet 82 from bore 76 for receiving a nipple 84 on plunger 67. Case 74 further comprises an annular groove 86 formed between two annular flanges 88 for retaining an outer O-ring 90.

[0027] Axial aperture 61 in hub portion 26 is surrounded by a short cylindrical flange 92 adjacent septum 48 within cup-shaped portion 46. Aperture 61 is surrounded at its outer extent (FIGS. 1 and 3) by a plurality of tangentially formed ramps 94 equal in is number to the number of lands 66 in cap 62 with which ramps 94 engage during assembly. A collar 96 surrounds ramps 94.

[0028] To assemble system 60 into cap 18, spring 68 is placed on plunger 67. Head 72 of plunger 67 is forced through opening 64 and retained therein. O-rings 80 and 90 are installed onto case 74. Case 74 is slid over plunger 67 and spring 68, nipple 84 extending through opening 82. Flanges 88 and O-ring 90 are pressed into cylindrical flange 92 and retained therein. The depth of bore 76 and the length of plunger 67 are selected such that when system 60 is assembled, flange 70 is urged by spring 68 against inner O-ring 80 to form a normally closed relief valve.

[0029] In use, pressure within vessel 10 may be relieved manually by rotation of cap 62. In rest position, lands 66 seek the valleys 98 at the base of ramps 94 in response to spring 68. Rotation of cap 62 drives lands 66 up ramps 94, thereby withdrawing flange 70 from contact with O-ring 80 and permitting escape of pressure from vessel 10 around flange 70 and along plunger 67. When relief cap 62 is released, spring 68 again urges lands 66 into valleys 98 and flange 70 against O-ring 80, closing the relief valve.

[0030] When the area of the end of nipple 84 and the strength of spring 68 are sized appropriately, as is well within the competence of one of ordinary skill in the art, system 60 may be configured to open automatically at a predetermined pressure level within vessel 10.

[0031] An important advantage of a pressure relief system in accordance with the invention is that the flange 100 of cap 62 overlaps collar 96 such that air and/or material being released from vessel 10 is directed downward toward hub portion 26, rather than upward toward as user, as in the prior art. Additionally, since peripheral extension 24 of hub portion 26 containing female threads 34 overlaps neck portion 12 containing male threads 16, any air and/or material that would be released from vessel 10 upon loosening of cap 18 would be directed downward and away from the user by peripheral extension 24.

[0032] Referring to FIG. 9, in an alternative thread configuration in accordance with the invention, neck 12 a is provided with male threads 16 a for sealing of cap 18 to vessel 10. Threads 16 a comprise variable pitch grooves formed in neck 12 a, terminating at the outer end of neck 12 a in a generally axial direction for receiving inwardly extending studs 34 a (FIG. 3) formed in cap 18 in lieu of threads 34. When cap 18 is placed on neck 12 a with studs 34 a engaged into the outer ends of grooves 16 a, rotation of cap 18 through one-quarter turn (90°) serves to draw cap 18 and O-ring 22 into sealing relationship with neck 12 a.

[0033] While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims. 

What is claimed is:
 1. A vessel cap for closing a threaded port in a vessel, comprising: a) a hub; b) a peripheral extension extending from said hub and having threads for engaging said threaded port whereby rotation of said cap opens and closes said port; c) an axial wall extending from said hub within said peripheral extension cooperating with said hub to define a cup-shaped portion of said vessel cap for use as a measuring device, when the said vessel cap is removed from said vessel, for ingredients to be added to said vessel.
 2. A vessel cap in accordance with claim 1 further including a septum extending across said hub portion.
 3. A vessel cap in accordance with claim 2 wherein said septum includes at least one step.
 4. A vessel cap in accordance with claim 1 wherein said cup-shaped portion includes indicia for indicating amounts of said ingredients present in said cup-shaped portion during said use as a measuring device.
 5. A vessel cap in accordance with claim 2 wherein said septum includes indicia for indicating amounts of said ingredients present in said cup-shaped portion during said use as a measuring device.
 6. A vessel cap in accordance with claim 1 wherein said axial wall terminates in an asymmetric rim defining a pouring lip.
 7. A vessel cap in accordance with claim 1 wherein an outer surface of said peripheral extension includes a designated area for receiving and displaying a label.
 8. A vessel cap in accordance with claim 1 further comprising a pressure relief system.
 9. A vessel cap in accordance with claim 8 wherein said pressure relief system comprises: a) a relief cap disposed outside said vessel cap; b) a plunger attached to said relief cap and extending through an opening in said vessel cap; c) a flange on said plunger; d) a spring disposed around said plunger in compression between said flange and said relief cap; and e) a case for receiving said plunger and flange to form a relief valve in said case, said plunger extending from said case.
 10. A vessel cap in accordance with claim 9 further comprising: a) a plurality of ramps formed in said vessel cap; and b) a plurality of lands cooperable with said ramps to cause said plunger to move axially in response to rotation of said relief cap.
 11. A vessel cap in accordance with claim 1 wherein said vessel is a pressure vessel.
 12. A vessel cap in accordance with claim 11 wherein said pressure vessel is a sprayer tank.
 13. A vessel cap in accordance with claim 1 wherein said threaded port includes a neck portion of said vessel.
 14. A vessel cap in accordance with claim 13 wherein an outer surface of said neck portion of said vessel includes said threads for engaging said vessel cap.
 15. A vessel cap in accordance with claim 1 wherein said peripheral extension threads include female threads and said port threads include male threads.
 16. A vessel cap for closing a port in a vessel, comprising: a) a hub; b) a peripheral extension extending from said hub and having at least one stud for engaging at least one variable-pitch groove disposed in a neck portion of said vessel whereby rotation of said cap opens and closes said port; c) an axial wall extending from said hub within said peripheral extension cooperating with said hub to define a cup-shaped portion of said vessel cap for use as a measuring device, when the said vessel cap is removed from said vessel, for ingredients to be added to said vessel.
 17. A vessel cap comprising a pressure relief system disposed in an opening through said cap.
 18. A method for measuring and entering an amount of material into a vessel through a threaded loading port, comprising the steps of: a) providing a vessel cap for closing said port, said cap including a hub, a peripheral extension extending from said hub and having means for engaging said threaded port whereby rotation of said cap opens or closes said port, an axial wall extending from said hub within said peripheral extension cooperating with said hub to define a cup-shaped portion of said vessel cap for use as a measuring device for ingredients to be added to said vessel, said cup-shaped portion including an indicium for indicating when said amount of said material is present in said cup-shaped portion; b) verifying that said vessel cap is removed from said vessel; c) orienting said vessel cap such that said cup-shaped portion is concave upwards; d) adding said material into said cup-shaped portion until the depth of added material equals the height of said indicium within said cup-shaped portion; and e) tipping said vessel cap to enter said added material into said vessel through said loading port. 